Evaporator for refrigerating systems



y 1930. R; w. DAVENPORT 1,769,116

EVAPORATOR 'FOR REFRIGERATING SYSTEMS Filed April L1927 INVENTOR. Ransom W flaw/ 00m JMJW A TTORNE Y.

Patented July 1, 1 930 UNITED. STATES PATENT OFFICE nmsou w. navnnronr, or ,nnrnorr, urcnrean, assrenon. 'ro onrcaeo rnnum'rrc moon COMPANY, on NEW YORK, 11. "2., a conrona'rron or NEW JERSEY nvaronaron non. nnrnrenna'rme srs'rnms Application mea April 5,1927. Serial are. 181,076.

This invention relates to refrigerating apparatus with particular reference to small mechanically operated refrigerating outfits, such as those intended for household use, in

' which it is desirable to freeze liquid in a relatively small chamber, while sufficient heat is extracted-from a larger chamber in which perishable articles, such as food may be preserved. More particularly, the invention re- 1 lates to refrigerating systems of the closed cycle typeutilizing as the refrigerant fluid a physical mixture of an evaporable liquid and of a gas substantially inert to and insoluble in the liquid, such as disclosed and claimed 15 and operating in accordance with the process disclosed and claimed in my Patent No. 1,619,196 of March 1st, 1927. One object of the invention is to provide improved means for evaporating a liquid to effect refrigeration at a plurality of temperatures and at a single total pressure. Another object is to utilize the refrigerating effect primarily for freezing. Still another object is to provide a simple. and compact evaporator unit adapted to be disposed in a food chamber and to elfect freezing of liquids while protecting the food chamber from the low temperature of the freezing compartment. Other objects will be apparent from the detailed description which follows:

Refrigerating systems which operate by straight evaporation, as in the reversed Clausius-Rankine cycle, provide means for extracting heat from both the freezing chamher and the refrigerating chamber at the same (q freezing temperature. In previous disclosures, such as my patent application No. 105,372 filed April 29th, 1926, I have set forth for evaporating liquids in a plurality of spaced evaporators into one or all of which the gas andvapor mixture of the refrigerant is expanded. Such. previous arrangements provide that the evaporators be spacedlaterally or vertically and be surrounded by zones or chambers operating at different temperatures.

The present invention aims to effect refrigeration in zones operating at different temin my Patent No. 1,619,194 of March 1st, 1927,

systems operating on the vapor-gas principle peratures also but with the distinction that one zone is inside the othe In the preferred arrangement the colder zone, for freezing water and other liquids, is contained within the higher temperature zone. In practice at least two evaporators are used, one of the evaporators being at least partly enclosed by the other. -Means are provided for causing two evaporators to absorb heat at different temperatures. This may be effected by utilizmg the vapor-gas principle and causing the expansion of the vapor-gas stream into the inner evaporator either solely or primarily. A single compressor may be arranged to provide the reduced pressure in both evaporators.-

' In order to illustrate the invention concrete embodiments thereof are shown in the accompanying drawings in which:

Figs. 1 and 2' are largely diagrammatic 7o viewsof closed cyclerefrigerating systems in which the evaporating means are shown in vertical section, the evaporators in Fig.

1 operating partly on the vapor-gas principle and partly straight cycle while the evaporators in Fig. 2 operate entirely on the vaporgas principle.

The closed cycle systems shown in Figs. 1 and 2 each have a pump or compressor A and a condenser B, these elements being of any so suitable" or desired type. The fluid withdrawn from the evaporator means by pump A is discharged into condenser B at higher temperature and pressure where it gives up its heat and the condensedliquid together with the gas and residual vapor in the system is fed back into one of the evaporator members through suitable means for passing both 7 liquid and gas, such for example as a Venturi nozzle C or' other fixed or variable orifice. The evaporating units may resemble in exterior configuration the conventional forms of evaporators heretofore used in the conventional or Rankine cycle systems.

' Evaporator unit D in Fig. 1 comprises an inner eyaporator 3 arranged tp be at least partly enclosed by additional evaporators 4 and 5. All the 1 evaporators open into a header 6, the outlet of evaporator 3 being by preference at a higher level than the outposed closely 10 to which 1 ts f a rators 'and 5. Pump withd rav s 3 8: and as-from header 6 th ro a connection F, t e inlet of which is d sreceptacle 7 whic may serve as a bafie plate d catch li uid passm toward thepump. if; shown, f eding devi ce C opens mm the bottom of evaporator 3 which contains liquid refrigerant and the products of condenser B are expanded directly theremto so that this evaporator operates on the vapor-gas rinci le producing a high absorption of eat om its immediate surroundings and creating a freezing zone within evaporator D. The space between the evaporator may be used to contain rece tacles 8 for water or other liquids to be ozen. The whole structure may be mounted in the usual way in the refrigerating chamber of a domestic refrigerator. Evaporators and 5 contain refrigerant hquid which is sub ected only to the low pressure reduced to ump A so that evaporation ta es place 0 y on the surface of the liquid in thesetwo eva orators which surface is in header 6, or a jacent thereto, with the result that evaporators 4 and 5 operate on theconventlonal or straight pumpmgcycle.

With the above arrangement the operatio is as follows: Upon starting the system, the a liquid in receptacles 8 is first frozen into ice by the low temperature efiect of the mner evaporator 3 before the outer evaporators 4 and 5 get very cold, although they are of course picking u some time the latentvheat of freezing is all or nearly all absorbed and the expansion in the outer evaporators 4 and 5 begin to get cold enough to ick up heat from the refrigerating 01111115161 at a high rate, thereby more rapidly cooling the an therein down to the required tem rature. Thus the effeet is to first rapi y freeze the liquid and then cool the refrigerating chamber."

The evaporating means in Fig. 2 comprises a central or inner evaporator 9 into which the products of condenser B are discharged through feeding device C so that this evaporator operates on the vapor-gas principle. Instead of discharging into header pump A is connected, the partly expanded gas together with the vapor of the re igerant liquid released in evaporator .9 is arranged to discharge into the enclosing eva orators 12 and 13 as by pipe '11. By pre eren'ce'evaporators 12 and 13 are interconnected at the bottom forming in effect a single evaporator and pipe 11 may lead to the interconnecting portion ofevaporators 12and 13. Outer evaporators 12, 13 are thus ugh adgacen'tto the bottom of a.

some heat from the,re-' frigeratmgcham r. After operating for A.. The inletfor ipe F may be disposed within a'bafiie' mem r14 as in the evaporator unit shown in Fig. 1. Since evaporators 12 and 13 are inseries with evaporator 9 and since the latter receive the 11111318101- pansion of the fluid from condenser E, eva orators 12 and 13 will operate at a hig er, temperature than'evapora'tor 9 1n accordance with the disclosure relative to dlfferential temperatures in systems operating on the vapor-gas principle as set forth in my co nding application, Serial No. 77,156, ed December 22, 1925,'which issued Au st 14, 1928, as Patent No. 1,680,453.

om the above it will be apparent that the present'invention aims to produce freezing ofliquid within the refrigerating chamher while protecting the latter against the freezing-temperature through the interposition of' an additional evaporator which operates at a higher temperature. 7

While preferred forms of the invention have been herein shown and described, it is to be. understood that the invention is not limited to the specific details thereof, but covers all changes, modifications and adaptations within the scope of the appended claims. 1

' I claim as my invention:

1. A refrigerating system of the closed cycle type operating on the-vapor-gas principle' having evaporator means 0 crating at a plurality of vapor pressures fiir providing two tem rture zories, one of said zones being within ,t e other.

2. A refrigerating system of the closed cycle type operating on the vapor-gas prin- :c1p le having evaporator means operatin at a plurality of vaporpressures for providing a 'gher temperature zone and a lower temerature zone, the lower temperature zone ein'g within the higher temperature zone.

3. A refrigerating system having an evaporator unit, a compressor, and a condenser, said parts being connected together to form a closed cycle system, said unit comprising an inner evaporator and an outer evaporator at least partly enclosing said inner evaporator, and means for eflecting absorption of heat by said-inner evaporator at a lower temperature than by said outer evaporator.

'4. A refrigerating system having an evaporator unit, a compressor, and a condenser, said parts being connected together to form a closed cycle system, said unit comprising an inner evaporator and an outer evaporator at least partly enclosing said inner' evaporator, and .means for operating said inner evaporator on the vapor-gas principle and for operating said outer evaporator at a higher temperature than said inner evapo-. rator.

5. A refrigerating system havin an evaporator unit, a compressor, and a con enser, said parts being connected together to form a i closed cycle system, said unit comprising an inner evaporator and an outer evaporator at least partly enclosing said inner evaporator, and means 'for operating both said evaporators on the vapor-gas principle but effecting initial expansion of the refrigerant medium in said inner evaporator.

6. In a refrigerating system the combination with a compressor and a condenser of an evaporator for liquid, means to feed liquid and gas from said condenser into said evaporator, a second evaporator partly surrounding said first evaporator, means to supply liquid to said second evaporator, and means to conduct vapor from both evapos rators to said compressor.

7 In'a refrigerating system the combination with a compressor and a condenser of an evaporator for liquid, means to feed liquid and gas from said condenser into said evaporator, a second evaporator partly sur-' rounding said first. evaporator, a header to which said evaporators are connected, and means connecting said header andsaid com pressor. I

8. In a refrigerating system the combination with a compressor and a condenser of an evaporator for liquid, means to feed liquid and gas from saidcondenser into said evaporator, a second evaporator partly surrounding said first evaporator, a header to which said evaporators are connected, a connection from said header to said compressor,

and bafiie means in said header adjacent the inlet to said connection. 9. An evaporator unit for refrigerating tional evaporators spaced from said central evaporator and at least partly enclosing the latter, a header for said evaporators, and means interconnecting said evaporators so that fluid entering said unit passes upwardly twice before reaching said header.

13. An evaporator unit for refrigerating systems operating on the vapor-gas principle comprising a plurality of evaporators, a

header to which said evaporators are connected, an outlet connection from said header, a

liquid collecting baflie within said header beneath said connections, and an inlet connection to one of said evaporators to cause the same to operate at a lower temperature than the remainder of said evaporators.

14. An evaporator unit for refrigerating systems operating on the vapor-gas principle comprlslng a central evaporator, addi-.

tional evaporators spaced from said central evaporator and at least partly enclosing the latter, a header for said evaporators, an outlet connection from said header, a liquid collecting bafile in said header beneath said connection, and means connecting said evaporators in series to cause fluid entering said unit to pass upwardly twice in a continuous pathbefore reachin said header.

Signed by me at etroit, in the county of Wayne, and State of Michigan this 31st day of March, 1927.

RANSOM w. DAVENPORT.

systems operating on the vapor-gas principle comprising a plurality of evaporators, a

header to which said evaporators are con nected, and connections whereby one of said I evaporators may be operated at a lower temperature than the remaining evaporators.

10; An evaporator unit for refrigerating.

systems operating on the vapor-gas principle comprising a central evaporator, tional evaporators at least partly surrounding said central evaporator, means interconnecting said evaporators to permit a single pump to withdraw vapor fgom all said evap orators and operating said .central eva orator at a lower temperature than the ot er evaporators. I a

11. An evaporator unit for refrigerating systems operating on the va or-gas principle. comprising a plurality o evaporators, a header to which said evaporators are connected, said evaporators bein disposed in spaced acin of containers for, liquids to e frozen, and

connections whereby one of said evaporators additherebetween may be operated at a-lower temperature than the remaining evaporators.

12. An evaporator unit for refrigerating systems operating'on the vapor-gas principle comprising a central evaporator, addi- 

